Oscillograph galvanometer



Ap 9, 1935- A. e. ZIMMERMAN OSC ILLOGRAPH GAIJVANOMETER 2 Sheets-Sheet 1 Filed Dec. 30, 1933 INVENTOR ARTHUR BY 2 MAN ATTORNEY April 1935- A. e. ZIMMERMAN OSCILLOGRAPH GALVANOMETER 2 Shaw-Sheet 2 Filed Dec. 30, 1933 IIIIIHIIIII HUN IIHIH INVENTOR ARTHUR G.ZIMME AN 7%? Patented Apr. 9, 1935 UNITED STA-TE- ,This invention more particularly PATENT- OFFICE" 1,996,783 I oscnmooulirn GALVANOMETEB.

Arthur G. Zimmerman,

of Delaware Westmont, N. L, assignor to Radio Corporation of America,

a corporation- Application December so, 1933, Serial No.:-704,808

's Claims. (01. 171-95) relates to galvanometers, and.

to the type of g'alvanometers used in film sound recording apparatus; The galvanometer is specifically intended for use in sound recording cameras 'wherein the sound is recorded directly on such, for example, as that disclosed in applica-' tion of Russell P. -May 11, 1933, and Batsel, Serial No.

The aforesaid recording device wherein ,May, Serial No. 670,417, filed in an application of C. N. 704,655, filed December 30,

applications involve a sound a movable mirror is actuated directly We diaphragm to record soundupon film. The galvanometer of this invention is intended to be substituted for such mirror and diaphragm when.

electrical operation is desired,

or it maybe built into or attached to any other type of film sound recorder.

eter on a Heretofore, it has been customary to adjust the position of a beam of light from a galvanom soundtrack by adjustment of the gal-' vanometer mechanism itself. In some cases, ad justment in one or-more planes was secured by bodily adjustment In compact portable apparatuses, such as those, of the beforementioned the galvanometer must be' rigidly attached toof the galvanometer casing.

applications, however,

and housed within the casing of the apparatus, and hence relative movement of the galvanometer casing and the film or optical system is impossible. In apparatus made according to my invention, I usegalvanometer mechanism of the type shown in Dimmick' Patent 1,936,833 issued' November 28, 1933, and adjustment of the mirror in relation to the remainder of that portion of the apparatus. is accordingly impractical. I

have accordingly devised a novel structure for mounting the galvanometer, mechanism which provides for adjustment therein in planes.

One object of means for rigidly securing a sound recording mechanism.

' Another object the invention is toFprovide galvanometer to of my invention is to provide means for completely enclosing the galvanometer with the sound recording mechanism.

Another object- .of my invention is to provide .means for adiustably supporting the galvanometer mechanism in relation to the sound record- 1118 mechanism.

Another object means for adjusting mechanism about of my invention is to provide the entire galvanometer' the mirror thereof as a center,

the picture film spherical surface 5. has

lies partly within different :head of the bolt a.

- longitudinal tensionxof holds the base of the mirror from the optical axis.

whereby the' adjustment will not displace the Another object of my invention is to provide such a device which can'be readily attached to' or detached from a sound recordingcamera.

In such apparatus as this galvanometer is intended for use in connectionwith, the galvanometer is attached to the rear of the'apparatus, and the mirror thereof faces :ffront. or back of the apparatus are used'in thezgalvanometer Fig. 3 is a rearview of the. galvanomete'r with the cover plate removed.

Fig. 4 is .a vertical section through the'galvanometer immediately adjacent to the vibrating armature.

As shown in the drawing athe galvanometer is housed in, and supported by, the casing or base member I which is provided with appropriate bolt-holes 4 for the purpose of attachment to the sound recorder. Theinterior of the mem-.

her I is provided with a spherically'curved sur-.

face 5 which serves as a seat for the correspondingly spherically curfved base of-the galvanometer 2. The galvanometer is provided with a mirror 3 which is vibrated by the armature 6 in response to audio frequency impulses, andthe the center of the. said mirror asits center of .curvature. 'fI'he'1a1Tm-ature 6 vibrates between 3| when influenced by currents passing through the coil 32 which surroundsthe armature and the polepieces as shown in It will be apparent that any movement of the galvanometer on the seat 5 willcause a'rotation of the-mirror 3 about its own center, but will cause I no other positional displacement of the mirror.

Attached to the base 2 of the galvanonieter is a plate -I provided with a curved seat for the 'Thisbolt 8' passes through the base I of the galvanometer, and adjacent its other end'carries-the nut 9 and washer washer I0 is pressed by the nut 9 against the coil spring H which in turn presses galvanometer- -2 firmly the pole pieces 30 and:

Ill. The

4 5o a a n theb member I of the galvanometer. It will be appare cut that the pressure of the spring ll produces a the, bolt 8, and'therebya the mirror about avertical axis is accomplished from the exterior of the casing l by the large nut I2. This nut works upon the spherically headed bolt l3 which passes through one side. of the galvanometer. When the nut I2 is tightened on the bolt, it accordingly pulls that side of the galvanometer toward the base member I and thereby adjusts the mirrorinth'at. direction about a vertical" axis. Movement in the-reverseidirection is accomplished by the spring I! placed between the base member'l and the'galvanometer 2, and surrounding the bolt 13. Itwill be apparcut that if the nut I2 is.- loosened, '-the spring I4 will force the corresponding side of the galvanometer outwardly, keeping it solidly against the head of the bolt l3 and effecting corresponding rotation of the galvanometer about a vertical axis a about a horizontal axis is accomplished by the screw I 5 which operates in the same way. As shown in Figs. 2 and 3, the screw I5 is not provided with a large nut, but is providedwith'a .tors of this cable I 9 and 20 carry the curre slotted head permitting its adjustment tobe performed-with the assistance of a screwdriver-or coin, as the adjustment about a horizontal axis needs to be performed-but rarely; whereas. the adjustment about the vertical axis must be quite functions addition to covering the bolt 8 with its attendant mechanism. As shown in Fig. 2, the cover l6 also serves as a protector for the nut l2. a

A supply cable I! is provided which carries current from the outputofthe amplifier to the galvanometer in order to actuate the mirror, .and

also supplies current to the exciter lamp of the recorder. This cable, as shown in Fig. 3, passes up through the bottom of the rear compartment of the member -I and .is secured by a clamp l8,

thereby providing a mechanically strong'and substantially storm-proof joint. Two of the conducthe amplifier through the rods'2ltothe galva-.

nometer' coil. A second pair of conductors 22 and 23in this same cable carry battery current to the rods 24 and 25.. These latter rods, as shown in- Fig. 2, are provided with pointed-contact ends and are pressed toward the recorder mechanism by the springs 26. when the galvanometer is secured into place on therecorder, the ends "of the. rods- 24 and 25 are therefore firmly pressed. against coresponding'contacts on the recorder case to which they transmit the exciter lamp current. M w

A cover 21, having the spacing ribs 28 built in-" tegral therewith, may be provided for protect ing the galvanometer from dirt and mechanical damage during transportation, and this covermay be secured to the galvanometer by the same Corresponding adjustment of the galvanometer nt from r 1,996,788 against the curved surface .5. Adjustment of screws ordinarilyused for attaching the galvanometer to the recorder or camera.

Having thus described my invention, I claim: 1. A galvanometer comprising a base member having a spherically concave face, a second base member carrying the galvanometer mechanism and having a spherically convex face, and means for yieldably maintaining said spherical faces in contact with each other. 1

2. A galvanometer comprising a base member having a spherically concave face, a second base member carrying the galvanometer-mechanism and having a spherically convex face, means for yieldably maintaining said spherical faces in contact 'with each other, and meansfor movingsaid .second base member in relation'tosaid first base member.

3. A mirror galvanometer comprising a base member having a spherically concave face, a sec- 0nd base member carrying the'galvanometer mechanism and having a spherically convex face with the mirror .located at the center of curvature of said face, and means for yieldably maintaming said spherical faces in contact with each other.

4. A' mirror galvanometer comprising a base member having a spherically concave face, a sec-- 0nd base. member carrying the galvanometer mechanism and having a spherically convex facewith the mirror located at the center of curvature ofsaid face, means for yieldably maintaining said spherical faces in contact with' each other, and means for moving said second base member in relation to said first'base member.

- 5. A. galvanometer comprising a base'member having a spherically concave face, a second base member carrying the galvanometer mechamsm.

and having a spherically convex face, means for yieldably maintaining said spherical faces in contact with each other, and means for moving said second base member about its center of curvature in relation to said first base member.

6. A mirror galvanometer-comprising .a base.

member having a spherically concave face, a sec- .,ond base 'member carrying the galvanometer mechanism and having a spherically convex face vvithfthe mirror located at the center of curvature of said face, means for yieldably maintaining said spherical faces in contact with each other, and means for moving said second base member about its center of curvature in relation to said first base member.

'7. A sound recording galvanometer comprising a. casing adapted to be rigidly attached toarecorder casing, galvanometer mechanism including means producing anfagnetic field and vibratable means in said field within said casing, and means for adjusting the entire galvanometer mechanism inrelation to said casing.

8. An oscillcgraph galvanometer comprising a casing adapted to be attached .to a recording device, galvanometer mechanism within said casing,

ing carrying electrical connections for said galvanometer whereby said galvanometer is protected from external atmospheric conditions.

and a separate closed compartment in said casas l 

